What matters more for longevity: genes or lifestyle?

When Dr. Nir Barzilai met 100-year-old Helen Reichert, she was smoking a cigarette. Dr. Barzilai, director of the Aging Research Institute at the Albert Einstein College of Medicine, remembers Ms. Reichert saying that doctors repeatedly urged her to quit smoking. But all the doctors died, Ms. Reichert noted, and she didn’t. Ms. Reichert lived for almost another decade before she died in 2011.

There are countless stories of people living to the age of 100, whose daily habits sometimes disregard conventional advice on diet, exercise, and the employ of alcohol and tobacco. However, decades of research show that ignoring this advice can negatively impact most people’s health and shorten their lives.

So how much of a person’s longevity can be attributed to lifestyle choices, and how much can be attributed to simply luck – or lucky genetics? It depends on how long you hope to live.

Research suggests that getting to 80 or even 90 is largely within our control. “There is very clear evidence that for the general population, a fit lifestyle does indeed extend life,” said Dr. Sofiya Milman, professor of medicine and genetics at Albert Einstein College of Medicine.

One study published last year, which analyzed the lifestyles of more than 276,000 U.S. veterans and veterans, found that adopting eight fit behaviors could add 24 years to people’s lives. These included eating a fit diet, regular physical activity, getting good sleep, managing stress, maintaining powerful relationships, as well as not smoking, misusing opioids and drinking excessively.

If veterans followed all eight behaviors, researchers calculated they could live to about 87 years of age. This probably sounds pretty good to most people; after all, it’s almost 10 years longer than life expectancy in the USA. But according to Dr. Milman, who was not involved in the study, the results showed that “even if you do everything right,” you still can’t expect to live to 100.

If you want to become a centenarian, you’ll need a little facilitate from your ancestors. Because the older someone gets, the more genetics seem to matter.

Generally speaking, scientists believe that this is as long as we live about 25 percent can be attributed to our genesand 75 percent can be attributed to our environment and lifestyle. But as people age around 100 and older, those percentages begin to reverse, says Dr. Thomas Perls, professor of medicine at the Chobanian and Avedisian School of Medicine at Boston University.

Indeed, studies have shown that many people live exceptionally long lives you don’t have healthier habits than the average American. Yet they live longer and this happens lower rate of age-related diseasessuch as heart disease, cancer and dementia.

In A long life family studyfor example: “We have families where there is a lot of smoking; in some families, they are couch potatoes,” said Michael Province, a professor of genetics and biostatistics at Washington University School of Medicine, who co-directed the study with Dr. Perls.

But these families also tend to have special gene variants that experts say facilitate them avoid disease and live longer.

Certain genes can influence the likelihood of developing certain conditions. For example, the APOE gene is known to influence the risk of Alzheimer’s disease: carriers of the APOE4 variant have an increased risk, while those with the APOE2 variant have a reduced risk. Dr. Province found that in long-lived families, the prevalence of APOE2 is higher than in the average population.

Other genes appear to influence the aging process itself. The one that has appeared in several studies of centenarians is called FOXO3which is involved in many fundamental aspects of cellular health. Because these genes influence the biology of aging, it is possible that they may protect against many age-related diseases, Dr. Milman said.

One of the key benefits of using these types of longevity genes may be the prevention of unhealthy behaviors. Test Research conducted by Dr. Milman and Dr. Barzilai comparing the offspring of centenarians with the control population showed that in both groups, people leading a fit lifestyle were characterized by a similarly low incidence of cardiovascular diseases. However, among those with unhealthy lifestyles, the offspring of centenarians still had low rates of disease, while those in the control group did not.

Experts stressed that many of these genes are very infrequent and are probably found in less than one percent of the population. (Probably not coincidentally, a similarly small percentage people live to be 100 years elderly.) There is also no single gene that provides protection against all aging processes and age-related diseases; it’s more likely that there are hundreds coming together to make a difference.

Having the right set of genes that influence longevity is “like winning the lottery,” Dr. Perls said. So even if your mom lives to be 100, you should still practice the behaviors you know are good for you, just in case you miss the mark.

And whatever you do, don’t listen to health advice from a centenarian. According to Dr. Barzilai, lifestyle probably didn’t matter much to them. For the rest of us, it really is.